A bath of corrosive chemical gives pretzels their dark crust
Food
The signature dark crust and chewy texture of a traditional German pretzel are the result of a brief dip in a skin-burning alkaline solution.
Before they enter the oven, authentic German pretzels are submerged in a bath of sodium hydroxide, a highly corrosive chemical with a pH level of thirteen. This harsh liquid breaks down the proteins in the flour, causing the dough to brown ten times faster than it would with steam alone. This process, known as the Maillard reaction, creates the deep mahogany color and a crust that is twice as tender as those made with common baking soda.